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fixed operator priority bug (see test program added in svn rev 232)

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git-svn-id: https://svn.code.sf.net/p/acme-crossass/code-0/trunk@238 4df02467-bbd4-4a76-a152-e7ce94205b78
This commit is contained in:
marcobaye 2020-06-17 00:37:19 +00:00
parent 326f36fd4f
commit 64aa52da35
2 changed files with 24 additions and 31 deletions
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53
src/alu.c
View File

@ -173,7 +173,7 @@ static int arg_sp;
enum alu_state {
STATE_EXPECT_ARG_OR_MONADIC_OP,
STATE_EXPECT_DYADIC_OP,
STATE_TRY_TO_REDUCE_STACKS, // FIXME - get rid of this state
STATE_TRY_TO_REDUCE_STACKS,
STATE_MAX_GO_ON, // "border value" to find the stoppers:
STATE_ERROR, // error has occurred
STATE_END // standard end
@ -699,6 +699,8 @@ static void list_append_list(struct listitem *selfhead, struct listitem *otherhe
// expression parser
// prototype (FIXME, re-arrange code so this is no longer needed!)
static void push_dyadic_and_check(struct expression *expression, struct op *op);
// helper function for "monadic &" (either octal value or "unpseudo" operator)
// returns nonzero on error
@ -741,7 +743,7 @@ static int parse_octal_or_unpseudo(void) // now GotByte = '&'
// Expect argument or monadic operator (hopefully inlined)
// returns TRUE if it ate any non-space (-> so expression isn't empty)
// returns FALSE if first non-space is delimiter (-> end of expression)
static boolean expect_argument_or_monadic_operator(void)
static boolean expect_argument_or_monadic_operator(struct expression *expression)
{
struct op *op;
int ugly_length_kluge;
@ -808,9 +810,8 @@ static boolean expect_argument_or_monadic_operator(void)
} else {
// non-empty list literal
PUSH_OP(&ops_start_list); // quasi-monadic "start of list", makes sure earlier ops do not process empty list
PUSH_OP(&ops_list_append); // dyadic "append to list", so next arg will be appended to list
// no need to TRY_TO_REDUCE_STACKS, because we know the one pushed first has a lower priority anyway
//stay in STATE_EXPECT_ARG_OR_MONADIC_OP
push_dyadic_and_check(expression, &ops_list_append); // dyadic "append to list", so next arg will be appended to list
//now we're back in STATE_EXPECT_ARG_OR_MONADIC_OP
}
break;//goto done;
@ -918,8 +919,7 @@ static boolean expect_argument_or_monadic_operator(void)
// that's either an empty expression or an erroneous one!
PUSH_INT_ARG(0, 0, 0); // push dummy argument so stack checking code won't bark FIXME - use undefined?
if (op_stack[op_sp - 1] == &ops_start_expression) {
PUSH_OP(&ops_end_expression);
alu_state = STATE_TRY_TO_REDUCE_STACKS;
push_dyadic_and_check(expression, &ops_end_expression);
} else {
Throw_error(exception_syntax);
alu_state = STATE_ERROR;
@ -948,7 +948,7 @@ now_expect_dyadic_op:
// Expect dyadic operator (hopefully inlined)
static void expect_dyadic_operator(void)
static void expect_dyadic_operator(struct expression *expression)
{
void *node_body;
struct op *op;
@ -1004,17 +1004,11 @@ static void expect_dyadic_operator(void)
case '[': // indexing operator
GetByte(); // eat char
PUSH_OP(&ops_atindex); // first put high-priority dyadic on stack,
// FIXME - reduce stacks!
PUSH_OP(&ops_subexpr_bracket); // then low-priority special ops_subexpr_bracket
// FIXME! this would work reliably if "atindex" had the highest priority.
// but function calls have higher priority than indexing:
// fn(a+b)[c] -> fn d [c] -> e [c], but the code above would return fn(d[c]) instead
// atm, it's not a problem, because all functions return numbers, and numbers cannot
// be indexed anyway, but in the long run, this must be fixed.
// maybe call "try_to_reduce_stacks" inbetween the two PUSH_OPs above?
// or maybe add a PUSH_DYADIC_AND_TRY_TO_REDUCE(op) macro?
alu_state = STATE_EXPECT_ARG_OR_MONADIC_OP;
// first put high-priority dyadic on stack,
// then low-priority special ops_subexpr_bracket
push_dyadic_and_check(expression, &ops_atindex);
// now we're in STATE_EXPECT_ARG_OR_MONADIC_OP
PUSH_OP(&ops_subexpr_bracket);
return;
// Multi-character dyadic operators
@ -1099,8 +1093,7 @@ static void expect_dyadic_operator(void)
get_byte_and_push_dyadic:
GetByte();
push_dyadic_op:
PUSH_OP(op);
alu_state = STATE_TRY_TO_REDUCE_STACKS;
push_dyadic_and_check(expression, op);
}
@ -2230,14 +2223,15 @@ static boolean handle_special_operator(struct expression *expression, enum op_id
// Try to reduce stacks by performing high-priority operations
// (if the previous operator has a higher priority than the current one, do it)
// FIXME - rename to "push_dyadic_op" and add operator arg?
static void try_to_reduce_stacks(struct expression *expression)
static void push_dyadic_and_check(struct expression *expression, struct op *op)
{
struct op *previous_op;
struct op *current_op;
PUSH_OP(op);
if (alu_state < STATE_MAX_GO_ON)
alu_state = STATE_TRY_TO_REDUCE_STACKS;
while (alu_state == STATE_TRY_TO_REDUCE_STACKS) {
if (op_sp < 2) {
// we only have one operator, which must be "start of expression",
// so there isn't anything left to do, so go on trying to parse the expression
@ -2319,23 +2313,22 @@ static int parse_expression(struct expression *expression)
op_sp = 0; // operator stack pointer
arg_sp = 0; // argument stack pointer
// begin by reading an argument (or a monadic operator)
alu_state = STATE_EXPECT_ARG_OR_MONADIC_OP;
PUSH_OP(&ops_start_expression);
alu_state = STATE_EXPECT_ARG_OR_MONADIC_OP;
do {
// check stack sizes. enlarge if needed
if (arg_sp >= argstack_size)
enlarge_argument_stack();
switch (alu_state) {
case STATE_EXPECT_ARG_OR_MONADIC_OP:
if (expect_argument_or_monadic_operator())
if (expect_argument_or_monadic_operator(expression))
expression->is_empty = FALSE;
break;
case STATE_EXPECT_DYADIC_OP:
expect_dyadic_operator();
break; // no fallthrough; state might
// have been changed to END or ERROR
expect_dyadic_operator(expression);
break;
case STATE_TRY_TO_REDUCE_STACKS:
try_to_reduce_stacks(expression);
Bug_found("TryToReduce", 0); // FIXME - add to docs or remove!
break;
case STATE_MAX_GO_ON: // suppress
case STATE_ERROR: // compiler

2
testing/errors/opnotsupp-FIXME.a → testing/errors/opnotsupp1.a
View File

@ -1,3 +1,3 @@
;ACME 0.96.5
li = [[9,8], 7, 3,4]
a = len(li)[0] ; this should give an "Operation not supported" error, but doesn't
a = len(li)[0] ; this should give an "Operation not supported" error